We are exploring the role the robot's physical embodiment plays in its abilities to engage, influence, and interact. We are examining the difference physical embodiment makes on social interaction, compared to non-physical but otherwise identical interactions (such as via smart phones, PDAs, and computers). We are interested in both better understanding and leveraging the growing evidence in favor of physically embodied robots over disembodied alternatives, showing that robots are particularly effective at engaging human users and shaping behavior. We are seeking to develop principled methods for controlling the robot's embodiment and expressiveness though "body language", including micro-social behaviors: proxemics (social spacing), oculesics (eye gaze), kinesics (gesture, posture, and facial expressions), and deixis (spatial referencing). Our research also spans the study of spatial language, embodied personality expression, embodied communication, and the coordination of multiple embodied communication channels/modalities, including gestures based on sentence content, structure, and timing, and appropriate references to locations of joint task-related attention.